In the past, orally disintegrating tablets have been developed as highly convenient forms which can safely be taken by patients who have difficulty in swallowing drugs, elderly people, children, etc., and which can easily be taken without water. It is important that the orally disintegrating tablets have sufficient breaking strength (tablet hardness) such that any cracks, powdering, etc. are not caused in the tablets during production or transportation of the tablets or during breaking their seals in the same manner as general tablets, and also, it is important that the orally disintegrating tablets have excellent disintegrability (disintegration time) such that the tablets immediately disintegrate in the oral cavity.
The tablet hardness and disintegrability are mutually opposing properties. In general, when a molding pressure is increased to increase the hardness, the disintegration time will tend to be prolonged, and, when the molding pressure is reduced to shorten the disintegration time, the hardness will tend to be smaller. Therefore, various technologies have been developed in order to cope with both the two properties or to achieve an optimal balance between the two properties.
Furthermore, the components of particles, granulation methods, etc. have been studied in order to impart superior moldability to the particles or particulate compositions constituting tablets.
It is well known that although the orally disintegrating tablets have improved medicine-taking compliance by patients, some patients having tendency to strongly reject the taking of medicine would vomit the tablets having the oral disintegration time in a range of bout 20-30 seconds. Accordingly, if a tablet has an extremely high disintegrability with the disintegration time of a few seconds, it can be easily administered to said patients since it will be disintegrated before they may feel uncomfortable when they take it.
Zydis (Registered Trademark) is known as a technique for the production of such tablet having an extremely high oral disintegrability, that is, an “ultrafast-disintegrating tablet.” This technique has been developed by Cardinal Health Co. (Catalent Pharma Solutions, LLC) for the production of an oral solid formulation. As shown in PTL 1, it comprises preparing suspension of bulk (medicinal ingredient) and mannitol using gelatin as a supporting material and filling the suspension into a blister, followed by freeze-drying to give a rapidly dispersing solid formulation for an oral administration.
Furthermore, PTL 2 discloses an invention relating to a method for the production of a multi-phasic, lyophilized, fast-dissolving dosage form. It is prepared by sequential dosing of a formulation containing a forming agent of non-gelling matrix and a formulation containing a forming agent of gelling gelatin, followed by freeze-drying to give a multi-phasic, lyophilized, fast-dissolving dosage form (FDDF) for the delivery of a pharmaceutically active ingredient. For example, non-gelling gelatin and gelling gelatin are used for the forming agents of non-gelling matrix and gelling matrix, respectively.